Effect of processing methods and storage time on chemical properties of palm oil

Abstract

The effect of four processing methods and the storage time on the chemical properties of palm oil were determined. The palm oil samples were extracted using hot extraction (HEPO), Cold extraction (CEPO), hot extraction with Sand (HSEPO) and Mechanized extraction (MEPO). Processing methods had no significant effect on the iodine value (45.94±0.68 to 47.06±2.25 wijis) whereas there were significant (p≤0.05) variations in saponification value (250.89±4.84 to 260.50±3.35mgKOH/g), peroxide value (8.59±4.14 to 12.08±4.70 mEq/kg), free fatty acid value (1.80±1.01 to 3.94±1.03%, mgKOH/g), acid value (3.77±1.91 to 7.90±2.08%, mgKOH/g) and carotenoids level (301.12±13.38 to 311.21±12.59 mg/kg) due to the processing methods. Storage time (months) caused no significant (p≤0.05) effect in iodine value (45.93±1.55 to 47.91±0.83 wijis) of palm oil samples stored for 0 to 3 month(s) but caused significant (p≤0.05) decrease in the carotenoids content (321.72±5.68 to 287.15±5.19 mg/kg). Storage time caused significant (p≤0.05) increase in saponification value (250.41±4.30 to 260.96±3.61 mgKOH/g), peroxide value (4.56±1.36 to 14.93±1.61%, mgKOH/g), free fatty acid value (1.83±0.84 to 3.77±1.32%, mgKOH/g) and acid value (2.45±1.74 to 7.54±1.80). Hot extraction method of palm oil was observed as the best method because its palm oil had the better quality parameter than other methods such as saponification value (252.20±4.00 mgKOH/g), iodine value (47.03±0.94 wijis), peroxide value (8.59±4.14 mEq/kg), free fatty acid (2.03±0.96%, mgKOH/g), acid value (3.94 ± 2.04%, mgKOH/g) and carotenoids level (302.90±13.46 mg/kg). Crude palm oil should not be stored for more than two months. It is recommendable to study the effect of storage conditions on the chemical properties of palm oil.